Automatic Swimming Pool Water Leveler Auto Fill With White Lid 1953-JW by MP Industries
The Auto-Lev is an accurate, easy to install device that will maintain exact water levels on pools, spas, hot tubs, fountains, ponds or water-holding tanks. It’s simple and easy-to-adjust float valve assembly is accurate and maintenance-free. Auto-Lev is constructed of durable high-impact plastic and sports a commercial grade. The plumbing port is a standard 1/2 female slip. The equalizer lines are 1 or 1-1/2 female slip. The top access lid is available in tan, white or gray to best fit your application. It also has a new accessory extension collar (4058) that raises the ring and lid 1.
WARNING: Product(s) shown and sold in the website and in store can expose you to chemicals which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to 
Andrew
Pathetic Manual but we use these and they are good. Install water with a pressure regulator.